Method of briquetting sawdust, peat, coal dust, and similar pulverous substances



Patented May 1, 1923.-

reiir HENRY AUGUST MUELLER, OF STOCKHOLM, SWEDEN.

METHOD OF BRIQUETTING- SAVVDUST, FEAT, COAL DUST, AND SIMILAR PULVEROUS SUBSTANCES.

No Drawing. Application filed June 25,

To aZZ whom it may concern:

Be it known that I, HENRY AUGUST MUEL- LEE, a citizen of the Kingdom of Sweden, residing at Stockholm Sweden, have 1nvented new and useful Improved Method of Briquetting Sawdust, Peat, Coal Dust, and Similar Pulverous Substances, for which I have filed application in Sweden, Feb. 16, 1918; Norway, March 17, 1920; Denmark, March 16, 1920; Finland, March 10, 1920; and of which the following is a specification. I

Briquettes as hitherto manufactured from saw-dust, peat, and similar substances have generally the drawback of not being sunciently resistant against the intluence of the moisture of the atmosphere. They are more or less destroyed it they are stored in the open air and may under some circumstances be completelybroken up. This depends essentially on the fact that according to the hriquetting methods hitherto used in the air which is contained in the pulverous mass to be briquetted is to a great extent enclosed in the briquettes and thus prevents the particles from com nginto a sufficiently intimate contact with each other.

This invention relates to a method of briquetting saw-dust, peat, and similar substances by which very resistant briquettes are obtained.

The invention consists, chiefly, in carrying out the briquetting operation in. such mannor that the air contained in the pulverous mass to be briquetted expelled by means of superheated steam as completely as pos sible immediately before the mass is briquetted. As the vapors thus substituted for the air in the mass on account of the high pressure applied to the mass in the briquetting operation are' condensed all particles come into an intimate contact with each other and very compact and hard briquettes are ob tained. A briquette manufactured in this 1920. Serial No. 391,786.

manner takes up water on the surface only when exposed to damp air or to rain while briquettes manufactured in usual way from saw-dust and the like rapidly take up water in their whole mass and will shortly be de-' stroyed. In briquettes of the last-mentioned kind the surface is softened by the water, and then the air enclosed in the briquette by the high pressure which was applied during its manufacture expands and causes the briquette to swell up until it falls into pieces.

Briquettes manufactured according to the present method obtain a higher specific weight than briquettes manufactured according to other known methods from the same materials. This fact shows that the particles must be brought nearer to each other by the pressure applied in the briquetting operation as compared with. the usual briquets ting operation without a foregoing eXpulsion of the air in the raw mass. I y

The materials to be briquetted should suitably be'cried to the same degree as when briquettingsuch materials in the usual way and they should, furthermore, suitabl 'be preheated to such degree that the -vapors used for expellin the air are notcondensed be fore the bri uettin ressure is a) lied.

Having now described my inventionl declare that what I claim is The method of briquetting" saw-dust, coaldust, air-dried peat and similar pulverous substances, which comprises supplying superheated steam to the pulverous until the air contained therein is essentially expelled, and then while the mass still contains oondensab'le yapors only applying pres' sure until the steam is condensed and the particles of the mass are brought into intinniuir AUGUST MUELLER; 

